Resistor and terminal connection



Aug. 18, 1931. A. .1. HANSON RESISTOR AND TERMINAL CONNECTION Filed NOV. 9, 1927 Patented Aug. 18, v1931 UNITED STATE-s PATENT ori-ica ALBERT HANSON, OF ARLTNGTON, MASSACHUSETTS, ASSIGNOB TO AMERICAN ELEC- TRIO FURNACE COMPANY, OF BOSTON, IASSACHUSETTSy A CORPORATION V01E' MASSACHUSETTS y BESIBTOB AND TERMINAL CONN ECTION Appleman ma november s, 1927. sei-m ma. zsaoas.

This invention relates to connections between terminals and resistor elements such as are used in electrical furnaces, more particularly resistors comprising relatively thin strips or ribbons of resistance material. In operation these resistors .become highly heated by electric current passing therethrough, but it is quite essential that the terminals which extend through the lfurnace wallsl shall pass the current to the resistors without excessiveheatinl and that the joints between the resistors an the terminals shall be good mechanically and electrically and so pass the heavy current without excessive local heating. In order that the terminal element shall be able to pass the heavy current satisfactorily and be at the same time readily insulated with a heat-resistant material where it `passes through the furnace stantially circular cross section and of a cross sectional area sufficiently larger than that of the resistor ribbon to pass the operating current without undue heating.

The resent invention relates particularly to the joint between the resistor ribbon and this terminal rod. Such a joint should be strong mechanically, suiiciently good electrically to pass the electric current without excessive heating, and cheap and easy to construct. It is'desirable also that the resistor ribbon be built up adjacent to the terminal rod in order to keep the heat low at the terminal, the heating temperature at the resistor commencing at a point spaced from the terminal rod.

According to this invention therefore a strip, preferably of the resistance material, is bent to form a loo intermediate its ends of sufficient size to c osely embrace the end of the terminal rod, the ends of this strip being spaced in parallel relation suiciently far apart to permit the resistance ribbon to be inserted therebetween with its end closely adjacent to the terminal rod. The parts are then welded together. By this construction the end portions of the strip reinforce the end of the resistor, thus increasing the cross sectional area for taking current so as to keep the heat of this portion of the resSQr wall, it is preferably made as a rod of subribbon down to proper limits. Of course, if

desired, additional short pieces of resistor e Figure 3 is a section on line '3V-3 of' Fi ure 1.

! igure 4f is a .section on line 4 4 of Figure 3. i

Fi re 5 is a section similar to Figure 3, but s owing an additional reinforcement for the resistor.

Referring lfirst to Figures 1 tov 4, at 1 is indicated a rod preferabl substantially circular in cross section an of sufficient cross sectional areaJ to carry the desired current without excessive heating. One end of this rod is shown of reduced diameter as at 2, and threaded as at 3 to receive the power cable connection.4 At 4 is shown a washer forming a shoulder between the threaded portion and the main body of the rod in order to rovide an abutment against which the cale securing devices maybe engaged when assembled on the rod. The .opposite end portion of the rod 1 may, if desired, be somewhat reduced in diameter as at 5 forming an annular shoulder 6 which helps to support the resistor connection as will later appear. The rod 1 may,V however, be of uniform diameter throughout its middle portion and the end portion where the metal resistor is secured.

Referring particularly to Figure 3, at 10 is shown .a strip of material, which may well be' a piece of resistor ribbon stock, having its intermediate portion as at 11 bent around to form a loop which takes over and embraces the portion 5 of the rod 1, its end portions 12 being spaced apart and in substantially parallel relation to `receive berelation the inner tween them in lappin 15, the extreme end of the resistor rib over the edge of the portion 11 and the end face of the rod 1 as at 17. On the opposite side of the resistor strip the weld may be in the form of a deposit of metal at 18 extending entirely around the rod 1, joining the portion 11 and the inner end of the resistor thereto.

In Figure 5 a somewhat modified construction is shown in which the resistor 15 is further reinforced by a strip 20 which is placed between the portions 12 of the edge strip in face to face relation with the resistor. By this means the cross sectional area of the resistor portion adjacent to the joint is still further increased so that the heating effect of the current passing therethrough is reduced.

It will be noted that with the construction herein shown it is unnecessary to perform any bending or forming voperations on the end of the resistor ribbon in order to secure it to the terminal, it being necessary only to cut off the resistor to the proper length to it between the ends of the strip which takes over and embraces the terminal rod. As the intermediate portions ofthe resistors are first formed up and the resistors are then assembled in the furnace, and the ends are thereafter secured to the terminals, this is of great advantage, as it is not easy to form said terminal connecting portions, particularly after assembly, and, if such portions are formed before assembly, a much greater accuracy and care in fabrication and assembly would be required and for the sole purpose of effecting such connections.

Certain embodiments of this invention having been described, it should be evident that further changes and modifications might be made therein without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. In combination, an electric furnace terminal rod, a ribbon resistor for high temperature operation, and a single strip having an intermediate portion formed to embrace said rod and its end portions lapping opposite sides of said resistor, said rod, resistor and strip being welded together.

2. In combination, an electrlc furnace terminal rod, a ribbon resistor for high temperature operation, and a strip of the width of said ribbon having an intermediate portion bent to embrace said rod at one end, its end portions extending laterally I signature.

ALBERT J HANSON. 

